Transponders are commonly used in optical signal transmission. An optical signal carrying data arriving from one optical fiber is converted by a transponder to an electrical signal and then sent across a conductive media to its destination where the data are used. The electrical signal with data may also be converted by the transponder to an optical signal and sent through the optical fiber to another destination. During the transmission of the data over the optical fiber or during the conversion of the data to electrical signals, errors may occur and these errors adversely affect the data.
The errors may be corrected through an error correction circuit. The optical signal or electrical signal may be processed by an external error correction unit before these signals are sent to other circuits for use. However, an external error correction unit adds to the complexity of overall design of a transponder-based retransmission unit.
An alternative approach is to incorporate the error correction unit into the transponder unit. This approach makes the resulting transponder unit more compact and eliminates the need for the external error correcting unit. However, this approach increases the number of data connectors that often exceeds the number of connectors allowed.
The error correction unit is usually implemented as an application specific integrated circuit (ASIC) that can be configured differently to conform to different operating conditions. Besides receiving signal data, the error correction unit also receives configuration data from an external source. Thus, the error correction unit requires a larger number of connectors for handling both the signal data and configuration data.
When the error correction unit is incorporated into the transponder, the number of connectors exceeds the limit that is imposed on the transponder and makes the combination circuit difficult, if not impossible, to fit within a traditional foot print for the transponder. It is thus desirous to have an apparatus and method that incorporates an error correction unit in a transponder without exceeding the connector limit for the transponder, and it is to such apparatus and method the present invention is primarily directed.